Hour angle Meaning, Definition & Usage

  1. noun the angular distance along the celestial equator from the observer's meridian to the hour circle of a given celestial body
  2. noun (astronomy) the angular distance of a celestial point measured westward along the celestial equator from the zenith crossing; the right ascension for an observer at a particular location and time of day
    HA.

WordNet

Definitions
  1. (Astron.), the angle between the hour circle passing through a given body, and the meridian of a place.

Webster 1913